FNC: An Advanced Anticancer Therapeutic or Just an Underdog?

Pharmacological Insights: Mitochondrial ROS Generation by FNC (Azvudine) in Dalton's Lymphoma Cells Revealed by Super Resolution Imaging

Nucleoside analogs are a common form of chemotherapy that disrupts DNA replication and repair, leading to cell cycle arrest and apoptosis. Reactive oxygen species (ROS) production is a significant mechanism through which these drugs exert their anticancer effects. This study investigated a new nucleoside analog called FNC or Azvudine, and its impact on ROS production and cell viability in Dalton's lymphoma (DL) cells. The study found that FNC treatment resulted in a time- and dose-dependent increase in ROS levels in DL cells. After 15 and 30 min of treatment with 2 and 1 mg/ml of FNC, mitochondrial ROS production was observed in DL cells. Furthermore, prolonged exposure to FNC caused structural alterations and DNA damage in DL cells. The results suggest that FNC's ability to impair DL cell viability may be due to its induction of ROS production and indicate a need for further investigation.

FNC (4'-azido-2'-deoxy-2'-fluoro(arbino)cytidine) as an Effective Therapeutic Agent for NHL: ROS Generation, Cell Cycle Arrest, and Mitochondrial-Mediated Apoptosis

Cytotoxic nucleoside analogs (NAs) hold great promise in cancer therapeutics by mimicking endogenous nucleosides and interfering with crucial cellular processes. Here, we investigate the potential of the novel cytidine analog, 4'-azido-2'-deoxy-2'-fluoro(arbino)cytidine (FNC), as a therapeutic agent for Non-Hodgkin lymphoma (NHL) using Dalton's lymphoma (DL) as a T-cell lymphoma model. FNC demonstrated dose- and time-dependent inhibition of DL cell growth and proliferation. IC-50 values of FNC were measured at 1 µM, 0.5 µM, and 0.1 µM after 24, 48, and 72 h, respectively. Further elucidation of FNC's mechanism of action uncovers its role in inducing apoptosis in DL cells. Notable DNA fragmentation and nuclear condensation point to activated apoptotic pathways. FNC-induced apoptosis was concomitant with changes in cellular membranes, characterized by membrane rupture and altered morphology. The robust anticancer effects of FNC are linked to its capacity to induce reactive oxygen species (ROS) production, prompting oxidative stress-mediated apoptosis. Additionally, FNC disrupted mitochondrial membrane potential (MMP), leading to mitochondrial dysfunction, further promoting apoptosis. Dysregulation of apoptotic genes, with upregulation of Bax and downregulation of Bcl-2 and Bcl-xl, implicates the mitochondrial-mediated apoptosis pathway. Furthermore, FNC-induced G2/M phase cell cycle arrest was mediated through modulation of the cell cycle inhibitor p21. Overall, this study highlights the potential of FNC as a promising therapeutic agent for NHL.

Safety Assessment of a Nucleoside Analogue FNC (2'-deoxy-2'- β-fluoro-4'-azidocytidine ) in Balb/c Mice: Acute Toxicity Study

OBJECTIVES

The present study aimed to provide an insight into the acute toxicity of a novel fluorinated nucleoside analogue (FNA), FNC (Azvudine or2'-deoxy-2'-β-fluoro-4'-azidocytidine). FNC showed potent anti-viral and anti-cancer activities and approved drug for high-load HIV patients, despite, its acute toxicity study being lacking.

MATERIALS AND METHODS

OECD-423 guidelines were followed during this study and the parameters were divided into four categories - behavioral parameters, physiological parameters, histopathological parameters, and supplementary tests. The behavioral parameters included feeding, body weight, belly size, organ weight and size, and mice behavior. The physiological parameters consisted of blood, liver, and kidney indicators. In histopathological parameters hematoxylin and eosin staining was performed to analyse the histological changes in the mice organs after FNC exposure. In addition, supplementary tests were conducted to assess cellular viability, DNA fragmentation and cytokine levels (IL-6 and TNF-α) in response to FNC.

RESULTS

In the behavioral parameters FNC induced changes in the mice-to-mice interaction and activities. Mice's body weight, belly size, organ weight, and size remained unchanged. Physiological parameters of blood showed that FNC increased the level of WBC, RBC, Hb, and neutrophils and decreased the % count of lymphocytes. Liver enzymes SGOT (AST), and ALP was increased. In the renal function test (RFT) cholesterol level was significantly decreased. Histopathological analysis of the liver, kidney, brain, heart, lungs, and spleen showed no sign of tissue damage at the highest FNC dose of 25 mg/kg b.wt. Supplementary tests for cell viability showed no change in viability footprint, through our recently developed dilution cum-trypan (DCT) assay, and Annexin/PI. No DNA damage or apoptosis was observed in DAPI or AO/EtBr studies. Pro-inflammatory cytokines IL-6 and TNF-α increased in a dose-dependent manner.

CONCLUSION

This study concluded that FNC is safe to use though higher concentration shows slight toxicity.

A Comparison of Etiology, Pathogenesis, Vaccinal and Antiviral Drug Development between Influenza and COVID-19

Influenza virus and coronavirus, two kinds of pathogens that exist widely in nature, are common emerging pathogens that cause respiratory tract infections in humans. In December 2019, a novel coronavirus SARS-CoV-2 emerged, causing a severe respiratory infection named COVID-19 in humans, and raising a global pandemic which has persisted in the world for almost three years. Influenza virus, a seasonally circulating respiratory pathogen, has caused four global pandemics in humans since 1918 by the emergence of novel variants. Studies have shown that there are certain similarities in transmission mode and pathogenesis between influenza and COVID-19, and vaccination and antiviral drugs are considered to have positive roles as well as several limitations in the prevention and control of both diseases. Comparative understandings would be helpful to the prevention and control of these diseases. Here, we review the study progress in the etiology, pathogenesis, vaccine and antiviral drug development for the two diseases.

Advanced prodrug strategies in nucleoside analogues targeting the treatment of gastrointestinal malignancies

Gastrointestinal malignancies are common digestive system tumor worldwide. Nucleoside analogues have been widely used as anticancer drugs for the treatment of a variety of conditions, including gastrointestinal malignancies. However, low permeability, enzymatic deamination, inefficiently phosphorylation, the emergence of chemoresistance and some other issues have limited its efficacy. The prodrug strategies have been widely applied in drug design to improve pharmacokinetic properties and address safety and drug-resistance issues. This review will provide an overview of the recent developments of prodrug strategies in nucleoside analogues for the treatment of gastrointestinal malignancies.

From synthesis to the biological effect of isoprenoid 2'-deoxyriboside and 2',3'-dideoxyriboside cytokinin analogues

Isoprenoid cytokinins are a class of naturally occurring plant signaling molecules. A series of prepared compounds derived from isoprenoid cytokinins (isopentenyladenine, trans-zeatin and cis-zeatin) with attached 2'-deoxy-d-ribose or 2',3'-dideoxy-d-ribose at the N⁹ position of the purine were prepared and their biological activities were examined. Different synthetic approaches were employed. The final compounds were characterized with variety of physicochemical methods (TLC, HPLC-MS, and NMR) and their cytokinin activity was determined in classical bioassays such as Amaranthus, tobacco callus, detached wheat leaf senescence and Arabidopsis thaliana root elongation inhibition assay. In addition, compounds were screened for activation of the cytokinin signaling pathway (bacterial receptor, competitive ligand binding and ARR5::GUS assay) to provide a detailed assessment of CK structure-activity relationship. The prepared compounds were found to be non-toxic to human cells and the majority of assays exhibited the highest activity of free bases while 2',3'-dideoxyribosides had very weak or no activity. In contrast to the free bases, all 2'-deoxyriboside derivatives were not toxic to tobacco callus even at the highest tested concentration (10^-4 moL/l) and compound 1 (iPdR) induced betacyanin synthesis at higher concentration even stronger than iP free base in the Amaranthus bioassay. The general cytokinin activity pattern base > riboside >2'-deoxyriboside > 2',3'-dideoxyriboside was distinguished.

Small molecules in the treatment of COVID-19

The outbreak of COVID-19 has become a global crisis, and brought severe disruptions to societies and economies. Until now, effective therapeutics against COVID-19 are in high demand. Along with our improved understanding of the structure, function, and pathogenic process of SARS-CoV-2, many small molecules with potential anti-COVID-19 effects have been developed. So far, several antiviral strategies were explored. Besides directly inhibition of viral proteins such as RdRp and M^pro, interference of host enzymes including ACE2 and proteases, and blocking relevant immunoregulatory pathways represented by JAK/STAT, BTK, NF-κB, and NLRP3 pathways, are regarded feasible in drug development. The development of small molecules to treat COVID-19 has been achieved by several strategies, including computer-aided lead compound design and screening, natural product discovery, drug repurposing, and combination therapy. Several small molecules representative by remdesivir and paxlovid have been proved or authorized emergency use in many countries. And many candidates have entered clinical-trial stage. Nevertheless, due to the epidemiological features and variability issues of SARS-CoV-2, it is necessary to continue exploring novel strategies against COVID-19. This review discusses the current findings in the development of small molecules for COVID-19 treatment. Moreover, their detailed mechanism of action, chemical structures, and preclinical and clinical efficacies are discussed.